This project builds upon previous work by the PI and others indicating that asymmetrical prefrontal activation derivedfrom brain electrical activity recordings is associated with both psychological and biological indices that reflect affective style. We have found that subjects with greater left prefrontal activation report more dispositional positive affect, have lower levels of basal cortisol, recover more quickly from a laboratory stressor and show higher levels of antibody titer following vaccination with influenza vaccine. During this grant period, we propose to test 400 MIDUS respondents on measuresof brain electrical activity under both baseline conditions and in response to affective stimuli. In addition, using emotion-modulated startle, we will assess startle modulation before, during and after the presentation of positive, negative and neutral pictures to derive indices of affective chronometry, or the time course of emotional responding. Brain electrical activity measures will be analyzed using both conventional spectral power estimates as well as source localization procedures. We predict that subjects with greater left prefrontal activation will show faster recovery following negative challenge. These individuals are also predicted to have lower cortisol (both basal and in response to challenge), lower levels of IL-6 and higher levels of psychological well-being. Analyses will also be conducted to ascertain the impact of cumulative adversity on these biological indices and to determine the extent to which measures of adversity account for variance in brain function and emotion-modulatedstartle over and beyond variance accounted for by contemporary measures of mood and well-being. The data from this project will provide significant clues to understanding the central mechanisms through which cumulative adversity and psychological well-being are instantiated in the brain and affect peripheral biology in ways that may be consequential for health.